The network-wide initiative will kick off tonight with hourlong primetime special City Underwater: Catastrophe in Houston, hosted by ABC News Chief Anchor George Stephanopoulos, at 10 PM EDT.

The special will focus on the ongoing relief effort, along with rescues and reunions taking place throughout the region. Chief National Correspondent Tom Llamas reports from downtown Houston. ABC News Senior Meteorologist Rob Marciano and correspondents Eva Pilgrim, Matt Gutman and Steve Osunsami are stationed in flooded areas where rescue efforts led by authorities, the Cajun navy and Lone Star Samaritans are underway. ABC News also follows the journey of a mother, who gave birth during the storm, and her family as they return to find their home destroyed. Chief Meteorologist Ginger Zee will join Stephanopoulos at ABC News headquarters with the most recent updates on where the storm will go next. The hour wraps with a salute to the stellar reporting done by KTRK-TV Houston during this difficult time.

The effort will continue Thursday, August 31. The previously announced call-to-action to donate to the American Red Cross will expand to all ESPN platforms and A+E networks, along with previously announced ABC, Freeform, Disney Channel, History, Lifetime, ABC Radio, Radio Disney and all network social platforms. At 8 AM EDT GMA will air a telethon encouraging viewers to donate to the American Red Cross, with the GMA team and special guests taking calls live until noon EDT. The fundraising will continue throughout the day on ABC’s eight owned stations, including Houston’s KTRK, as well as on more than 200 local affiliates.

Disney chairman and CEO Robert Iger and KTRK-TV Houston previously announced they were committing $1 million to the American Red Cross for hurricane relief efforts